hybrid solid state amps

Pathos amps use a tube front end and ss output stage. Don't know about their size and cost, though.

I assume you mean power amps, but the Pathos Classic One integrated fits your bill, too.

Marty

Musical Design

http://www.musicaldesign.com/MD_T100.html

LSA designs is another. I have heard a few and the Moscode is a lovely amp, but not that cheap. Pathos make few, from the Classic to the TT, which was known as the Twin Towers, the Logos, Inpol, all integrated, right up to the Incontrol monoblocks.
I have the Inpol and it truly is a wonderful amp, 50 watts of Class A power, refined detailed, tonally rich. I can't really make any complaints at all. It is more than your price limit, but within it, second hand. If you can manage with 35watts, the TT is great too. The logos is Class A/B and to my ears, markedly inferior to the Class A amps.

There is also the Aesthetix Atlas. All of the reviews have been favorable and it's a great sounding amp.

Good Luck!

Unison Research (Italy) also does some interesting hybrid products at and well below your budget.

For your budget you may be able to find a second hand AMR AM-77 which is a hybrid from the UK.